Multicolor sheet fed rotary printing machine



NOV. 2%, 1938. w HUCK MULTICOLOR SHEET FED ROTARY PRINTING MACHINE Filed Oct. 12, 1957 7 Sheets-Sheet I INVENTOR. 7

NOV. 29, 1938. HUCK MULTICOLOR SHEET FED ROTARY PRINTING MACHINE Filed Oct. 12, 1957 7 Sheets-Sheet 2 INVENTOR.

Nov. 29, 1938. w F. HUCK J 9 MULTICOLOR SHEET FED ROTARY PRINTING MACHINE Filed Oct. 12, 195'? 7 Sheets-Sheet 3 IN V EN TOR.

Nov, 29, 1%38. F HUCK MULTIGOLOR SHEET FED ROTARY PRINTING MACHINE Filed Oct. 12, 1937 '7 Sheets-Sheet 4 Nov. 29, 1938. w. F. HUCK MULTICOLOR SHEET FED ROTARY PRINTING MACHINE 7 Sheets-Sheet 5 Filed Oct. 12, 1957 mvEN'roR.

Nov. 29, 1938. w uc 2,338,407

MULTICOLOR SHEET FED ROTARY PRINTING MACHINE Filed Oct. 12, 1937 7 Sheets-Sheet 6 Nov. 29, 1938. I FQHUCK 2,138,407

MULTICOLOR SHEET FED ROTARY PRINTING MACHINE Filed OCtf'lZ, 1937 7 Sheets-Sheet 7 Y IN"ENTOR.

' Q; g 2a ATTORNEY.

Patented Nov. 29, 1938 UNITED STATES MULrIooLoP.

SHEET FED, ROTARY PRINT- llNG MACHINE William F. Huck, Richmond Hill, N. Y., assignor to R. Hoe & 60., Inc., New York, N. Y., a corporation of New York Application October 12, 1937, Serial No. 168,583

12 Claims.

The invention disclosed in this application which is a continuation in part of my co-pending application, Serial No. 25,589, filed June 8, 1935, relates in general to multi-color sheet fed rotary printing machines and has for its object the provision of an improved machine of the kind described, with a view to a more convenient, expeditious and efficient feeding, printing and delivery of sheets.

A particular object of the invention is to provide novel improved means for guiding an endless, gripper-carrying flexible traveling member or carrier and for locking and accurately registering the grippers carried thereby to the impression cylinders.

Another object is to provide an improved gripper mechanism, having means particularly designed and adapted to assure a gradual change in the direction of movement of the gripper carriers as the chains conveying same enter and leave curved portions of their paths.

It is also an object of the invention to provide a multi-color sheet fed rotary printing machine of generally improved construction, which will be simple, durable and inexpensive in construction, as well as convenient, practical, serviceable and eflicient in its use.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts, and in the details of construction hereinafter described and claimed, it being understood that various changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

While the invention is particularly adapted for use with multi-color printing machines where two or more colors are printed in superposed relation to one another, the invention is also applicable to sheet fed mechanism where a single color is imposed.

The preferred embodiment of the invention is illustrated in the accompanying drawings, where- Figure 1 is a diagrammatic view showing a four unit multi-color printing machine equipped with web cutting and sheet transferring mechanism, sheet conveying means and sheet deliverymechanism;

Figure 2 is a view showing a portion of a printing machine similar to that depicted in Figure l and illustrating a multi-color printing machine wherein a conventional type of sheet feeder is employed which takes out sheets from a pile and feeds them to the printing units;

Figure 3 is an enlarged fragmentary elevational view illustrating the sheet gripper mechanism employed, including means for accurately registering it with respect to an impression cylinder; I

Figure 4 is an enlarged fragmentary vertical sectional view of certain details of the gripper support, as taken on the line and as viewed in the direction of the arrow 4 of Figure 3;

Figure 5 is a fragmentary plan view, partly in section, of the gripper mechanism, as viewed in the direction of the arrow 5 of Figure 3;

Figure 6 is a cross section taken on the line 6-45 of Figure 5, looking in the direction of the arrow;

Figure '7 is an enlarged fragmentary elevational view of the front end of a modified form of chain-conveyed sheet gripper mechanism (not shown in application Serial Number 25,589), the relative position of the carrier chains and one of the coacting sprockets being indicated in dotted lines for the purpose of clearer illustration;

Figure 8 is an enlarged fragmentary plan view of the front end portion of the mechanism shown in Figure 7;

Figure 9 is a plan view, similar to Figure 8, of the opposite or rear end of the mechanism;

Figure 10 is a transverse sectional view taken on the line III-l0 of Figure 9, as seen in the direction of the arrows;

Figure 11 is .a View similar to Figure 10, taken on line lll| of Figure 9, as seen in the direction of the arrows, the sheet clamping and sheet releasing positions of the gripper fingers and certain of the coacting parts being shown in full and dotted lines respectively;

Figure 12 is a detail sectional view, taken on line |2 |2 of Figure 8, as seen in the direction of the arrows; and

Figure 13 is a transverse sectional view taken on line I3-I3 of Figure 8 looking in the direction of the arrows, the gripper actuating cam, normally positioned only at the feeding and delivery ends of the apparatus, being included to show the relative position of the coacting parts when a sheet is being fed to the gripper conveying assembly or delivered therefrom.

The invention disclosed in this application directed more particularly to means for gradually changing the direction of motion of the gripper carrier as the conveying chains enter and leave curved portions of their paths. This effect is achieved by the hereindescribed mechanism, without the necessity of employing specially constructed chains having one or more links of unusual size, as required in conventional sheet conveyor devices. An exceptional smoothness of action is attained by the instant mechanism,-

which is greatly conducive to high speed operation of the machine as a whole.

Hitherto, sheet gripping mechanism of the type employing chain-carried grippers have developed serious defects in operation, such as a III slapping or whipping action in their rapid orbital or curved movement, and a proneness to irregular or uneven seating in the receptacles or sockets provided for them on the impression cylinder. As a direct consequence of this, the register of the superposed colors printed has been seriously affected. The present invention is also specially designed and adapted to obviate the defects noted and to permit the attainment of operating speeds hitherto impractical by reason of the facts mentioned.

In Figures 1 and 3 to 6 inclusive of the drawings wherein similar characters of reference indicate corresponding parts in the several views, the numeral 3 designates the frame of a sheet fed printing machine embodying one form of the invention whereon are arranged web control or tension mechanism 4, web feeding mechanism including gear driven rolls and guides designated generally at 5, web cutting cylinders 6, I, having knives 8, 9, sheet forwarding rollers I0, sheet guides II, a battery of printing units A, B, C, D respectively, adapted to print in several colors, and a delivery mechanism E. The web control or tension means 4 and the delivery mechanism E, may be of any well known and approved construction and need not be further referred to here. The web cutting cylinders 6, I and the web feeding mechanism 5 which latter includes either a replaceable or change gear I2 that may be substituted by other gears of different values; or a variable gear drive unit of conventional design (not shown) ,are of the general design and construction shown in patent to Zuckerman, No. 1,558,140, dated October 20, 1925 for Web cutting mechanism.

Each of the printing units comprises inking means, designated generally at I3, form and blanket cylinders I4, I5 respectively, and an impression cylinder I6; so that a description of one printing unit will serve for all.

All of the printing units mentioned are operatively joined and actuated by a drive shaft I'I, provided with a plurality of worms I8, each engaged with a gear (not shown) on the shaft I9 of each adjacent blanket cylinder I5. Th: drive shaft I1 is also provided with a pair of additional worms 2|, 22, one worm 2I being engaged with a worm wheel (not shown) on the shaft of a cylinder 23 coactingly engaged with a cylinder 23' and forming a part of the delivery mechanism, and the other with a worm wheel (not shown) on the shaft of the upper transfer cylinder 24 of apair of cylinders, as

hereinafter described.

In Figure 2, a modified form of the invention is disclosed having a battery of three printing units B, C, D, each comprising form, blanketand impression cylinders I30, I3I and I32 respectively. The units B, C, D, it is understood, are of the same type as those shown in the first form of the invention illustrated diagrammatically in Figure l, and are operated from a common shaft I33 having a plurality of worms I34, each of which meshes with a worm wheel on the shaft I35 of each blanket cylinder I3l. In the instant form of the invention, however, sheets are fed from a pile type feeder L which is adapted to handle cut sheets taken from a pile and deliver them to a pair of cylinders I36, I31 by means of sheet forwarding rollers I0. Over a sprocket wheel fastened to each end of the cylinder I31 an endless flexible carrier or conveyor I38 is engaged. Each of the flexible carriers I38, one of which is arranged at either end of the several impression cylinders I32 has attached thereto sheet gripper supports or units indicated generally at M (Figure 3).

Each gripper unit M comprises a pair of bifurcated plates or bars E39, each having a slot I49 and an opening HH and joined to the adjacent flexible carrier or chain I38 by screw studs or bolts I42, I43. The stem of the screw stud I42 is fitted to slide in the elongated slot I40. The screw stud I43 has rotatably mounted thereon a sheave or roller I44 which is arranged in the opening MI. The flexible carriers I38 which convey the gripper assemblies M, are normally guided and supported on sprocket .wheels I45, each of which is fastened to its adjacent impression cylinder I32- in any suitable manner.

Between the opposed arms I49, I41 of each bar I39 and in the opening I4I thereof, a cam roller I 48 is rotatably arranged on a bearing I49, supported on a stud I5I, fastened in the opposed arms I46, I41 of the said bifurcated, The arms'or straps I46, I 41 of the mem-,

bar.

ber I39 being of a length equivalent to several of the links of the chain, and in passing around the impression cylinder, the arms take a position that may be considered as the chord of an arc, while the position of the links more nearly defines the arc. The difference in length of the two paths will result in motion of the pins I in the slots I40. The pivot pin I43 in each pair of the arms I46, I4! is located on the trailing sides of the grippers, and it will be observed that after the grippers have passed the line of impression between the printing cylinder and the impression cylinder, and the chain movesinto aedges of rings sprocket wheel I45 which also has secured thereto in any suitable manner segmental plates I53, I54. The plate I53, as best shown in Figure 3, is adapted to serve as an abutment for the.

lower edge of the bifurcated bar I 33, while the plate I54, which has a V-shaped face I55, is adapted to engage the groove of the sheave I44 (Figure 4).

Secured to one arm of each bifurcated bar I39 and extending between the pair of said bars I39 is a T-shaped bracket or rail member I56. Across the length of the member I56 there is secured, at intervals, a plurality of bracket members I51, best shown in Figures 5 and 6, of such construction as to allow for the insertion of gripper members I58 between side members or arms I59, IGI, each bracket I5! further providing a clamping seat I62 upon which the said gripper members I58 will clamp the sheet or product, when acting in conjunction therewith.

The under portion of the clamping seat I62 is provided with a pocket I63 into which one end of a spring I54 is seated. Each bracket member I5! is provided with a short shaft I65 upon which is mounted the gripper member I58, said gripper member being further provided with 75 l The flexible carrier or chain I38 is partly supported on the upper- I 52 suitably fastened to each Uli journal receiving-portions I66 wherein is carried a shaft I61 having a cam roller I68 rotatably mounted thereon, the shaft I65 being held in place on the bracket I51 by a pin (Figure Each gripper member I58 in addition, is provided with an extended portion I18 having a pocket I1I into which the other end of the a spring I64 is seated, the said spring applying pressure between the clamping seat I62 and the gripper member I58.

The cam roller I68 is adapted to be received at predetermined intervals in a notch I12 provided on a shaft I13 to which a member or bracket I14 is clampingly secured by a screw I15 (Figure 3).

The shaft I13 extends across the length of the impression cylinder and has reduced ends I16 which extend through the head of the member I56 and into the arms I46 of the oppositely disposed bifurcated bars I39. Rotatably mounted on the stem of a stud I11 suitably secured to the bracket I14 is a cam roll I18, the said roll positioncd on the frame adjacent the cylinder I31, the said cam having a raised portion which is effective to temporarily open the grippers I58 against the action of the springs I64 in order to receive a sheet from the feeder L, the sheet thereafter being immediately seized by the prompt closing of the grippers as the cam roller I18 passes over a depressed portion of the same cam, and permits the cam roll I68, on the gripper-carried shaft I61, to be received in the notch I 12 of the shaft I13. The sheet is then conveyed through the printing units B, C, D, to

" 'a delivery mechanism (not shown) which may be of the general type as that designated E in Figure 1, at which point the sheet is released by the action of the other cam I19 and the elements I coacting therewith, and delivered to a pile by the said delivery mechanism.

A further advantage of the invention will be appreciated from an examination of Figure 3 of the drawings from which it will be observed that the gripper carrier, which may be considered as having its center of gravity near the axis of the shaft I65 travels at the speed of the chain when the latter is moving in a straight line; that it travels at an appreciably slower speed when passing the point at which it is depicted in Figure 3 because of its shorter radial distance from the cylinder axis; and that the transition from the higher to the lower speed is made gradually, as the gripper carrier moves toward and away from the impression point of the cylinders. This action, it will be observed, is caused by the mounting of the gripper carrier on the arms I46, I41. By moving the gripper carrier on a shorter radius as it passes the impression point, it is subjected to less centrifugal force and this arrangement in combination with the parabolic path provided for the chain results in greatly increasing the smoothness of operation of these portions of the machine.

In the modified form of gripper carrier which is illustrated in Figures 7 to 13 inclusive, and

the several impression cylinders 2I I. A flexible carrier or chain 2I2 positioned at either end of the impression cylinders, as in the other form of the invention, is operatively engaged with each sprocket, and has attached thereto sheet gripper supports or carrier units indicated generally at R (Figure '1) whose functions are analogous to those described in the first form of the invention but which differs therefrom in certain details of construction, as hereinafter described.

Each gripper supporting unit R comprises on one side, as best shown in Figures 8 and 9, a pair of elongated plates 2I3, 2I4 arranged in spaced relation and accommodating therebetween at one end aroller 2I5 rotatably mounted on a stud 2I5 secured to the adjacent portion of the chain and extending through the said plates 2I3, 2I4. The roller H5 is confined against axial movementby collars or washers 2I6, 2I6 also arranged on the same stud 2I5.

At their other end, the plates 2I3, 2M have hingedly secured thereto upwardly extending, spaced arms or extensions 2", 2I1', which are arranged to swing on studs 2I8' secured to each pair of plates 2I3 and 2I4, the said arms having registering openings at their upper ends to accommodate a stud 2I8 whereon a roller 2I9 is rotatably mounted.

In a similar manner, the gripper supporting unit R on the side opposite to that shown in Figure 8, further comprises plates or links 2I3', 2I4' arranged in spaced relation and accommodating therebetween a sheave 220 rotatably mounted on a stud 228' fastened to the adjacent chain and extending through the plates 2I3, 2M, the sides of the sheave 220 being juxtaposed against the adjacent sides of the last mentioned plates and thereby prevented from axial movement. The plates 2I3, 2I4 correspondingly to the plates 2I3, 2I4 also have spaced arms or extensions 22I, 22I provided with registering openings accommodating a stud 222 on which a roller 223 is rotatably mounted.

The sheave 220 and roller 223 above described, seat on members 224, 224 suitably fastened to the adjacent sprocket wheels 2Ill (Figure 10) which are secured to the reduced hubs of their respective impression cylinders and may be of the general type shown in my copending application Serial Number 25,589, referred to above. The rollers 2| 5, 2|!) correspondingly seat on a pair of members, only one of which is shown, fastened to the adjacent sprocket.

Between the opposed plates 2I3, 2M, a cam or pressure roller 225 is rotatably arranged on a bearing 226, supported on a stud shaft 221,

Suitably fastened to or integrally formed with an inner side of the plate 2I4' is a split bracket or extension 23I provided with spaced, threaded lugs 232, 233', through which screws 234 are passed (Figure 10), the said lugs and screws serving to clampingly and adjustably confine a gripper supporting tube or member 235. A somewhat similar bracket 23I, integrally formed on the inner face of the plate 2I4, is provided at the other or front end of the assembly, as. best shown in Figure 8, for the purpose of securing the adjacent and opposite end of the gripper supporting tube 235.

Upon the periphery of the outer tube 235, as best shown in Figure ll, grippers are secured. Each gripper comprises a resilient lower plate or finger 235 having an arcuately shaped body portion adjustably fastened to the said tube by screws 23'! threadedly engaged in the tube 235. The body portion of the finger 236 is folded and bent to provide a jaw 239 adapted to coact and engage with a jaw 24l provided on a second plate or finger 242 which is fastened at one end to the top of the finger 238 by screws and nuts 243.

A second tube 244 is rotatably supported within the outer tube 235 by a series of bushings or sleeves 246, each of which is retained in position in the tube 235 by screws 240'.

At one end of the second tube 244, a bushing 245 is fastened, the said bushing receiving a bearing 246 wherein the journal portion of a stud shaft 247 fastened to the plate 2M is accommodated (see Figure 12). The stud 241 has an annular flange 248 seated against the side of the plate 2l4, and a reduced portion protruded through the said plate and enclosed by a retainer cap 249.

portion 239 of the lower finger 236 to receivea sheet therebetween at a predetermined time, the member 25! then moving with the inner tube 244 to permit the upper finger to return to clamping engagement with the said sheet in order to convey same through the printing units.

The inner tube 244 adjacent the plate 2l4 has secured thereto a bracket 253, best seen in Figure 13, the split hub or body portion of which is clampingly and adjustably secured to the said tube 244 by a screw 254. The bracket 253 has a bifurcated extension which projects outwardly of a recessed portion 236 of the bracket 23! which supports outer tube 235, the said extension having opposed arms 255, 256 which are formed with registering openings wherein a stud 257 is suitably secured.

. A cam roller 259 is rotatably mounted on the stud 251 and adapted to be engaged by a cam 266 arranged adjacent the transfer cylinders at the feeding end of the printing units, shown diagrammatically in Figures 1 and 2, for the purpose of separating the jaw 24l of the upper spring biased gripper finger from the jaw of the lower gripper finger in order to receive a sheet, the cam 260 then operating to permit the said upper finger to return into normal closed and sheet clamping position. Another of the cams 266 is positioned adjacent the cylinder 23l and the cylinder I32 at the delivery ends of the above referred to printing units for the purpose of again opening the gripper fingers to release the sheet to the delivery mechanism, after its passage through the printing units.

A compression spring 26| encircles a pin 262, fastened to a bracket 263, secured by a screw 264 to the tube 235. One end of the spring 26! is seated on the bracket 263, the other'end being seated on a bracket 265 in turn secured to the bracket 253 by the clamping screw 254 above mentioned, whereby the inner and gripper actuating tube 244 and the lever arm 25l secured thereto are biased in a counterclockwise direction to the normal inoperative position shown in full lines in Figure 11, as hereinbefore described.

The function and mode of operation of the modified form of the device which is analogous tothat described above in connection with the other form of the invention may be summarized as follows:

When a sheet being forwarded from the feeder L in the manner hereinbefore described, arrives adjacent the lower transfer cylinder I24 of the arrangement shown in Figure 1 or the lower cylinder l3! of the arrangement shown in Figure 2 at which point it overtakes or meets one of the traveling gripper units R on the chain, the cam 266 will be engaged by the cam roller 259, thereby turning the inner tube 244 with its lever arm 25l in a clockwise direction, and consequently, moving the jaw 24l of the upper resilient gripper member 242 away fromthe lower jaw 239, as shown in dotted lines in Figure ll, in. order to receive the sheet which is then clampingly engaged upon the return of the said upper gripper jaw to its normal closed position, as shown in full lines in Figure 11. The sheet thereafter is conveyed through the series of printing units, to the delivery mechanism where it is released by the action of the other cam 266 to the delivery mechanism. As the sheets are carried by the grippers through the various units by the chain conveyed grippers, it will be understood that each of the gripper. assemblies R are in turnthrust against the segmental plates, fastened to the sprockets while passing over the latter, by the action of the cams 22B and coacting cam rollers 225, in the manner described above in connection with the other form of the invention.

The supporting of the grippers on links which are secured to the chains at points spaced apart a distance equal to a plurality of chain links, as pointed out above, results in a marked smoothness of movement while the gripper carriers are passing around the sprockets, not possible to devices wherein each gripper support is mounted on adjacent links of the chain or on a single enlarged link extending a space equal to several links. The results achieved in the instant device are substantially equivalent to those set forth in the paragraphs above concerning the other form of the invention, the gripper carriers moving at the speed of the chain when the latter is traveling in a straight line, and at an appreciably slower speed when passing over the sprockets.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, and it will be further understood that each and every novel feature and combination present in or possessed by the mechanism herein disclosed forms a part of the invention included in this application.

What I claim is:

1. In a printing machine of the character described, a sheet conveyor adapted to receive sheets and convey the said sheets to and through a printing unit and thence to a delivery, said conveyor including a pair of endless chains with links of substantially uniform length and a gripper carrier having grippers adapted to engage the sheets, said gripper carrier being so sup- 15 ported at'two points on each chain as to permit movement of the carrier relative to the chain at one point, said points being separated by a plurality of links, whereby the direction of motion of the gripper carrier is changed gradually as it enters and leaves curved portions of its path.

2. In a printing machine of the character described, a sheet conveyor adapted to receive sheets and convey the said sheets toand through a printing unit and thence to a delivery, said conveyor having a pair of endless chains with links of substantially uniform length and a gripper carrier having grippers adapted to engage the sheets, said gripper carrier being supported on 'each chain at two points separated by a plurality of links, by a member pivotally connected at one of said points and having means connecting the member to the other point in a manner permitting movement of the carrier relative to the chain at the last mentioned point, whereby the direction of motion of the gripper carrier is changed gradually as the parts of the chain to which it is connected enter and leave curved portions of their paths.

3. In a printing machine of the character described, a sheet conveyor adapted to receive sheets and convey the said sheets to and through a printing unit and thence to a delivery, said conveyor having a pair of endless chains with links of substantially uniform length and a gripper carrier having grippers adapted to engage the sheets, said carrier being supported on each chain at two points separated by a plurality of links and having a pair of means concentric to a common axis, said grippers being fastened to one of said pair of means, gripper operating means connected to the other of said means, and cam means for actuating the gripper operating means at predetermined times.

4. In a printing machine of the character described, a sheet conveyor adapted to receive sheets and convey the said sheets to and through a printing unit and thence to a delivery, said conveyor having a pair of endless chains with links of substantially uniform length and a gripper carrier having grippers adapted to engage the sheets, said carrier including members supported on each chain at two points separated by a plurality of links, a hollow member connected to and extending between the members, said grippers being fastened to said hollow member, a second hollow member arranged within and turnable relatively to the first hollow member, gripper-actuating means secured to the second hollow member, and a stationary cam for operating the gripper actuating means at predetermined times.

5. In a printing machine of the character described, a sheet conveyor adapted to receive sheets and convey the said sheets to and through a printing unit and thence to a delivery, said conveyor having a pair of endless chains with links of substantially uniform length and a gripper carrier having grippers adapted to engage the sheets, said gripper carrier being supported by each chain at two points separated by a plurality of links, an adjustable tubular member forming a component of the said carrier, said grippers being removably secured to the tubular member, a second member turnably mounted within the tubular member, a gripper operating arm secured to the second member and protruded through the tubular member to open said grippers a fixed cam, and means operated thereby for moving said second member at predetermined times.

6. In a printing machine of the character described, a plurality of printing units, flexible sheet-conveying means, a plurality of members mounted on and movable relatively to said conveying means, and a sheet gripper mechanism connected to each of said members, movement of said members relatively to the sheet conveying means serving to appreciably relieve tension on the sheet during a printing operation.

7. In a printing machine of the character described, a plurality of printing units, flexible sheet-conveying means, a plurality of gripper supports mounted on and movable relatively to said conveying means, and a sheet gripper mechanism pivotally connected to each of said supports, movement of said supports relatively to the sheet conveying means during a printing impression serving to relieve tension on the sheet after said sheet has begun to be operated upon.

8. In a printing machine, a plurality of printing units, flexible sheet conveying means formed by a plurality of connected elements of determined length, and sheet carriers including means to engage the sheets and having components supported at two points by the flexible sheet conveying means, said points being separated by a plurality of the elements of the sheet conveying means.

9. In a printing machine, a plurality of printing units, flexible sheet conveying means formed by a plurality of connected elements of uniform length, and sheet carriers including means to engage the sheets and having components supported at two points by the flexible sheet conveying means, said points being separated by a plurality of the elements of the sheet conveying means.

10. In a printing machine, a plurality of printing units, flexible sheet conveying means formed by a plurality of connected elements of determined length, and sheet carriers including means to engage the sheets and having components supported at two points by the flexible sheet conveying means, said points being separated by a plurality of the elements of the sheet conveying means, one of the points being movable relative to the said sheet conveying means.

11. In a printing machine, a plurality of printing units, flexible sheet conveying means formed by a plurality of connected elements of sub stantially uniform length, and sheet carriers including means to engage the sheets and having supporting components supported at two points by the said flexible conveying means, the points being separated by a plurality of the elements of the flexible conveying means, one of the points being fixed relative to the said conveying means and the other movable relative thereto.

12. In a printing machine, a plurality of printing units, sheet conveying means having endless flexible elements operably supported by a plurality of spaced rotatable members, and sheet carriers including means to engage the sheets and having supporting components, each component being supported at two spaced points by a flexible element, one of the points being fixed relative to the flexible element, and the other movable relative thereto whereby the movable point moves closer to the fixed point in passing around the said rotating members.

WILLIAM F. HUCK. 

